The whole molluscan assemblages along the Turkish coasts of the Aegean Sea and the Levantine Sea (Southern Turkish coasts), were studied from 20 stations at depths ranging from 11 m to 69 m, between August and October 2014. This has resulted in new contribution to Mediterranean marine molluscan fauna. Crithe cossinea is a new lessepsian for the Mediterranean Sea, five Gastropoda (Melanella alba, Mangelia callosa, Mangelia tenuicosta, Clathromangelia loiselieri, Raphitoma bicolor) are new records for Turkish Seas, two Gastropoda (Ondina obliqua, Retusa nitidula) are new records for the Aegean Sea while another two Gastropoda (Alvania hispidula, Vexillum hypatiae) are new records for the Turkish coast of the Aegean Sea and four Gastropoda (Cerithiopsis fayalensis, Bela menkhorsti, Raphitoma aequalis, and the alien species Monotygma fulva) are new records for the Turkish coasts of Levantine Sea. Among Bivalvia species, Thyasira alleni is a new record for both seas and Pitar mediterraneus is a new record for the Turkish coasts of Levantine Sea. The present study contributes to molluscan fauna of Turkish waters by the addition of six more species, increasing their number to 1076.